This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Polycystic Ovary Syndrome (PCOS) causes oligo-ovulation, and is often accompanied by elevated androgens (hirsutism and/or acne), insulin resistance, and elevated luteinizing hormone (LH). PCOS is usually treated with pharmaceuticals (oral contraceptives, metformin, fertility drugs). In our pursuit of the biological mechanism underlying acupuncture as a non-drug treatment for PCOS, there is a gap of knowledge on the role of beta-endorphins ( Endo). LH is released in a pulsatile fashion by the brain, but is secreted at high levels throughout the month in PCOS. Endo is also pulsatile, acts to suppress LH in normo-ovulatory women, and Endo is generally higher in PCOS than normally cycling women. Preliminary data from our acupuncture randomized clinical trial indicates that Endo levels normalize and LH levels are reduced in PCOS women when they become ovulatory. In order to improve our ability to design a larger study, we will gather preliminary data on the secretory pulse characteristics of Endo in untreated PCOS women. Specifically, this study will collect continuous blood samples over a standardized 8-hour time period (q10 blood sampling) in 4 untreated PCOS women. Serum will be assayed by ultrasensitive chemiluminescence (LH,) and column chromatography/ELISA ( Endo) assays. Our aims are to a) assess varying sampling paradigms in hopes of reducing the frequency of blood sampling for Endo in future studies;(b) assess the relationship between Endo and LH secretory pulse characteristics;c) describe the Endo secretory pulse characteristics in untreated PCOS women. The significance of this proposal for our future research is financial (high expense of Endo assays at $55/sample discounted research price compared with ovarian hormones at $3/sample discounted research price) and practical (volume of blood needed for Endo is 4 mL compared with 1 mL for LH). This knowledge is critical to the budget and protocol for our R01 grant on the biological mechanism of acupuncture for PCOS awaiting resubmission (AT004700).